Caliper mechanism for lapped sheets fed to a printing press or the like

ABSTRACT

A caliper mechanism for lapped sheets which uses, as a sensor, a chamber filled with conducting liquid and enclosed by a diaphragm which is acted upon by roller riding on the moving sheets. Extending from the chamber is a neck having a contact at its upper end, the cross section of the neck being only a small fraction of the area of the diaphragm so that as the roller rises a column of liquid rises in the neck at an amplified rate for making of contact. An individual sensing mechanism is distinguished by use of a cylindrical mount which is secured to supporting framework and which, in turn, serves to support a cylindrical sensing unit, the members being threadedly telescoped together to permit separate adjustment of normal roller position and the roller displacement necessary to cause contact. In the preferred construction two such mechanisms are coupled to separate rollers arranged end-to-end, each mechanism having a series of contacts at progressively higher level. Corresponding contacts in the two units are connected, as pairs, to output signal lines by logic circuitry so arranged that no signal is produced as long as the rollers occupy substantially the same level within the range of maximum anticipated thickness. At the end of each series is a final contact which bypasses the logic circuitry and which is capable of producing a signal for stopping the conveyor when the maximum anticipated thickness is exceeded.

Waited States Patent [72] Inventor Clayton C. Claybourn Northbroolt,Ill. [21] Appl. No. 86,188 [22] Filed Nov. 2, 1970 [45] Patented Dec. 7,1971 [73] Assignee North American Rockwell Corporation Pittsburgh, Pa.

[54] CALIPER MECHANISM FOR LAPPEI) SHEETS FED TO A PRINTING PRESS 01RTHE LIKE 20 Claims, 10 Drawing Figs.

[52] 11.8. CI 271/57, 192/127, 226/45, 340/259 [51] Int. Cl B65h 43/04[50] Field of Search 271/47, 57, 56; 192/127, 126; 33/147 8,147 L, 147N, 143 L, 148 H, 172 E; 340/259; 226/45 [56] References Cited UNITEDSTATES PATENTS 1,515,774 11/1924 Jones 271/47 3,228,681 1/1966 Williamset a1.. 271/57 3,516,513 6/1970 Robertson et al 182/19 FOREIGN PATENTS508,786 6/1939 Great Britain 271/57 Primary Examiner.loseph WegbreitAssistant Examiner-Bruce H. Stoner, Jr. Attorney-Wolfe, Hubbard, Leydig,Voit & Osann ABSTRACT: A caliper mechanism for lapped sheets which uses,as a sensor, a chamber filled with conducting liquid and enclosed by adiaphragm which is acted upon by roller riding on the moving sheets.Extending from the chamber is a neck having a contact at its upper end,the cross section of the neck being only a small fraction of the area ofthe diaphragm so that as the roller rises a column ofliquid rises in theneck at an amplified rate for making of contact. An individual sensingmechanism is distinguished by use of a cylindrical mount which issecured to supporting framework and which, in turn, serves to support acylindrical sensing unit, the members being threadedly telescopedtogether to permit separate adjustment of normal roller position and theroller displacement necessary to cause'contact. 1n the preferredconstruction two such mechanisms are coupled to separate rollersarranged end-toend, each mechanism having a series of contacts atprogressively higher level. Corresponding contacts in the two units areconnected, as pairs, to output signal lines by logic circuitry soarranged that no signal is produced as long as the rollers occupysubstantially the same level within the range of maximum anticipatedthickness. At the end of each series is a final contact which bypassesthe logic circuitry and which is capable of producing a signal forstopping the conveyor when the maximum anticipated thickness isexceeded.

PATENTEDBEB Hen 1625509 SHEET 1 OF 3 Iuvzuron CARLTON C. CLAYBOURIVCALIPER MECHANISM FOR LAPPED SHEETS FED TO A PRINTING PRESS OR THE LIKEIn the supplying of sheets of paper to a sheet-fed printing press it iscommon to cut sheets from a continuous web, the severed sheets beingthen deposited upon a conveyor to form a stream of overlapping sheetswhich are turned over to become a stream of underlapping sheets forfeeding directly to the press. Experience shows that the stream oflapped sheets will include sheets of irregular length, sheets which arefolded, sheets having turned corners, which are misaligned, or sheetswhich have between them lumps of foreign matter. Moreover, sheets may befed in double thickness. It is essential that all such defects bedetected, and corrected, before they reach the press and cause damage.

The problem of detection is complicated by the overlapping; thethickness of the stream, as it passes under the roller, is not constantbut varies cyclically in accordance with the degree of overlap. Thus,the actual thickness at any given point is not as significant as whetherthe total anticipated thickness has been exceeded or the fact that thereis variation in thickness as measured transversely of the direction offlow.

Devices have been produced for many years for monitoring a stream ofsheets and for stopping the conveyor upon encountering unusualthickness. Moreover, devices have been proposed for detecting thecondition of differential thickness at points spaced transversely of thedirection of flow. However, such devices have, for the most part,required complex mechanical linkages including long and relativelyflimsy levers which are easily bumped out of adjustment and which areexpensive to construct, install, and maintain. Moreover, priormechanisms employing mechanical linkages have been subject to inertialforces and have been usable only for relatively thick sheets. They havenot been capable, for example, of reliably distinguishing between threesheets having a total thickness of 0.006 inch and four sheets having atotal thickness of 0.008 inch. Reliability suffers especially at highproduction rates where inertial forces are more pronounced.

It is, accordingly, an object of the present invention to provide acaliper for a stream of lapped sheets which is reliable and positive inoperation even where used with thin sheets transported at a high rate ofspeed. Thus, it is an object to provide a caliper for lapped sheetswhich, though highly sensitive, is nevertheless stable and largelyfreely of inertial effects to minimize the possibility that theconveyor, and press being fed, may be shutdown unnecessarily.

It is another object of the present invention to provide a caliper for astream of lapped sheets which avoids the exposed mechanical linkagesformerly used in this type of device and their susceptibility to damageupon inadvertent bumping by a pressman as he carries out his duties. Itis, more specifically, an object to provide a caliper which is compactand self-contained, which avoids use of mechanical levers or linkages,which has a minimum of moving parts and which is not only sensitive butrapidly responsive to changes in thickness as the sheets are fed at ahigh production rate. It is another and related object of the presentinvention to provide a caliper which is immune to accidental damageincluding that which might result from excessive movement of thecalipering rollers.

It is yet another object of the present invention to provide a calipermechanism which employs a pair of calipering devices which are coupledto rollers arranged end to end and which is distinguished by sets ofprogressive contacts with associated logic circuitry so that an outputsignal is produced only when a differential thickness exists across thewidth of the stream or when the thickness at any point in the streamexceeds a predetermined maximum value.

It is yet another object of the invention to provide a caliper mechanismwhich is capable of handling thin sheets with any degree of overlapping,which may be easily and quickly adjusted to existing conditions, inwhich the adjustment, once made, is accurately maintained until anintentional change is made in the operating conditions, and whichrequires substantially no maintenance.

The other objects and advantages of the invention will become apparentwhen reading the attached detailed description and upon reference to thedrawings, in which:

FIG. I is a front elevation of a simple form of calipering installationconstructed in accordance with the present invention;

FIG. 2 is a side view of the mechanism shown in FIG. I looking along theline 22 and with the transverse frame member in cross section;

FIG. 3 is a vertical enlarged section taken along the line 3- 3 in FIG.1;

FIG. 4 is a top view of the device shown in FIGS. 1-3;

FIG. 5 is a front view, similar to FIG. 1, but showing a modified andpreferred form of the present invention;

FIG. 6 is a fragmentary plan view looking along the line 6- 6 in FIG. 5;

FIG. 7 is a side view corresponding to FIGS. 5 and 6;

FIG. 8 is a top view of a sensing unit used in the modification of FIG.5 and looking along the line 88 in that FIG;

FIG. 9 is a developed sectional view looking along the line 88 in FIG. 5and showing use of a plurality of adjustable contact used in the twosensors; and,

FIG. I0 is a schematic diagram showing the output circuit and the logiccircuitry which forms a part thereof.

While the invention has been described in connection with certainpreferred embodiments, it will be understood that I do not intend to belimited to the particular embodiments shown but that I intend, on thecontrary, to cover the various alternative and equivalent constructionsincluded within the spirit and scope of the appended claims.

Turning now to FIGS. I and 2, there is disclosed a conveyor 10 having abelt 11 which carries an underlapped stream of sheets indicated at 81-84and which are exaggerated in thickness for the sake of illustration. Theconveyor belt II, is at a reference position, diverted, or offset, by agroup of pulleys 12 for accommodation of a lower caliper roller 13, theupper surface of which serves as a reference for gaging of thickness.Aligned above the roller 13 is an upper calipering, or sensing, roller15 having two portions pinned at 16 for vertical swinging movement upona horizontal supporting arm 17 (FIG. 2). The latter is pivoted at 18 toa depending bracket 19 which is secured to a transverse hollow framemember 20.

In accordance with the present invention, a sensing assembly for sensingmovement of the calipering roller I5 is provided which includes a liquidchamber having an upwardly extending neck portion and enclosed, at thebottom, by a diaphragm which is connected, by means of a plunger, to thecalipering roller. A contact is mounted in the neck and the neck is of across-sectional area which is only a small fraction of the area of thediaphragm so that when the roller moves upwardly a column of the liquidis forced upwardly in the neck at an amplified rate for engaging thecontact whenever an unusual thickness is encountered. Thus, referringparticularly to FIG. 3, a caliper device 30 is provided having a sensingassembly 31 formed of a cylindrical base 32 and a superimposed housingor cap 33 which is preferably formed of insulating material and which ishollowed out to form a fluid chamber 34. The lower wall of the chamber34 is defined by a flexible diaphragm 35, the peripheral edge of whichis firmly anchored between the presented edges of the members 32, 33 asshown. Extending downwardly from the diaphragm is a plunger 36 fittedwith a disc-shaped head 37 which underlies the diaphragm and which issecured to it. Means, to be discussed, are provided for coupling theplunger 36 to the roller 15 so that the diaphragm is moved upwardly anddownwardly in accordance with the vertical movements of the roller asdifferent thicknesses are encountered.

Communicating with the chamber 34 and extending upwardly from it is anarrow neck portion or passage 40 having a cross-sectional area which isonly a fraction of the area of the diaphragm so that when the diaphragmis raised, the liquid rises in the neck at an amplified rate. For makingelectrical contact when the liquid rises to a predetermined level, acontact screw 41 is provided which is threaded into an insert 42 andwhich presents a pointed tip 43. After the tip 43 is set at the desiredheight the adjustment is maintained by tightening a clamping nut 44.

In order to prevent damage to the sensing assembly as a result of excessupward movement of the plunger 36, the lower end of the plunger isprovided with a stop in the form of a collar 45 which engages adownwardly presented stop surface 46 on the member 32. The diaphragm 35and plunger 36 are maintained in a normally bottomed condition by meansof a coil spring 47 which exerts a downward force against the collar 45,the disc-shaped head 37 serving as a stop in the downward direction.

In order to transmit the movement of the roller to the lower end of theplunger 36, a lower plunger is provided arranged coaxially end to endand which extends downwardly to a captive connection with the roller.This lower plunger, indicated at 50, is mounted for sliding movement ina cylindrical mount 51 having a flange 52. The plunger 50 has a headportion 53 and a hollow shank portion 54 which is enclosed, at its lowerend, by a threaded ferrule 55. Mounted in the ferrule is a plungerextension 56 which is pivoted at pivot 57, at its lower end, to an am 58which is secured to the shaft 16 upon which the roller 15 is mounted.The lower plunger 50 is maintained extended downwardly, in bottomedcondition, by a coil spring 59 which presses against a flange formedintegrally with the ferrule 55.

In order to permit the plunger assembly to yield endwise for safety'ssake, in the face of any excessive upward movement of the roller 15, ayieldable joint is provided between the plunger member 50 and thedownwardly extending member 56. Such a yieldable joint is formed by astifi coil spring 60 which is included within the hollow shank 54 andwhich presses against the head 56a of the member 56. Thus, in the faceof all normally imposed forces or roller displacements, the plungermembers 50, 56 remain stiffly bottomed with respect to one another withthe spring 60 in its extended position. However, upon excess upwarddisplacement of the roller, and with the plunger members 36, 50 beingblocked against further movement, compression of the spring 60 occurspermitting upward movement of the member 56 to accommodate the rollermovement.

ln order to adjust the normal position of the roller, the mount 51 isexternally threaded for reception in a threaded hollow receiver which issecured to the transverse frame member 20. Thus, as shown in FIG. 3, themember 51 has an external thread 65 which screws into an internal thread66 formed in the hollow receiver 67 which is firmly secured to thehollow frame member by means of cap screws 68 or the like. Where it isdesired to support the upper caliper roller 15 in direct contact withthe lower caliper roller 13 to establish an initial position for theroller 15, the mount 51 is rotated by the flange 52 at its upper end,the mount 51 being turned clockwise until the roller 15 just makescontact. At this point the mount 51 may be clamped in place within itsreceiver 67 by means of a clamping nut 70 having an operating arm 71.

For the purpose of adjusting the sensing assembly so as to produce apredetermined displacement of the liquid in chamber 34 in response to apredetermined upward displacement of the roller 15, the base 32 of thesensing assembly, which is of cylindrical shape, is externally threadedat 75 for telescoped screwing into an internal thread 76 formedconcentrically within the mount 51. In adjusting this threadedconnection, a calibrating shim representing the maximum tolerablethickness of the sheet may be inserted between the lower and upperrollers 13, 15. Following this the sensing assembly may be screweddownwardly into the mount 51 until the upper plunger 36, bottomingagainst the lower plunger member 50, raises the diaphragm so that theliquid is forced well up into the narrow neck portion. In the event thata fixed contact is used, the sensing assembly may be screwed in untilthe liquid engages the contact to close an electrical circuit, followingwhich the sensing assembly may be backed of slightly. It may then beclamped in position, relative to the mount 51, by a clamping nut 77having a handle 78. In the preferred embodiment, using an adjustablecontact, the sensing assembly may be screwed in until contact isachieved and then clamped in place by the nut 77. As a final step thecontact screw 41 may be backed off slightly and then clamped in positionby clamping 44. It will be apparent, then, that adjusting thedisplacement of the upper caliper roller required to produce electricalcontact is a matter of making two coordinated adjustments, the bodilyadjustment of the sensing assembly and the adjustment of the contactscrew. Since the roller displacement for lapped sheets of conventionalthickness will be exceedingly small, the sensing assembly is preferablyadjusted, with respect to the mount 51, so that contact with the lowerplunger is achieved, under initial conditions, at point 79 at the lowerend of the plunger 36. Thus, any upward movement of the roller 15 isimmediately accompanied by proportional upward movement of theconducting fluid in the neck 40, with the adjustment of the contactscrew 41 determining when contact, as a function of roller displacement,will take place. However, where larger amounts of roller displacementwill normally occur, for example, in the calipering of heavy-gage paperor cardboard, the sensing assembly may be adjusted by backing off sothat there is separation at point 79 under the initial condition. Wheresuch separation is utilized, it will only be the final portion of theroller movement, following bottom at point 79, which will cause risingof the liquid in the neck. In this way high sensitivity and accuracy maybe preserved even when dealing with relatively thick sheet material.

When using the simplified form of the invention, with a single detectingcontact a simple output circuit suffices. Such output circuit may, forexample, include a relay 80 having a normally closed contact 81 which isin series with the winding of the existing trip solenoid 82 forming apart of the regular conveyor and press control circuit. Thus, whencontact is made and the relay coil 80 is energized, the normally closedcontact 81 opens thus permitting the trip solenoid 82 to drop out toturn off the conveyor and stop the feed.

It will be apparent that this detecting arrangement, even in itssimplified form, carries out many of the objects of the presentinvention. It is sensitive to small roller displacements since thecross-sectional area of the neck 40 is many times smaller than the areaof the diaphragm 35 to which the roller 15 is connected, thus giving ahigh amplification ratio. Stated in practical terms, movement of theroller through 0.002 inch, corresponding to the thickness of a thinsheet of paper, and which imparts the same displacement to the diaphragm35, is effective to cause a rise in the liquid column through a muchgreater distance. When the area ratio is, say lOO, the column of liquidwill rise in the neck 0.2 inch. To detect the double thicknesscondition, the screw 41 may be set to product contact at 0.4 inch abovethe reference level, providing a range which insures against spuriouscontact.

Since the mechanism is almost entirely self-contained it is not subjectto bumping or mechanical damage during the normal activity of theoperator of the conveyor and press. Nor is it possible for the device todamage itself as a result of extreme roller displacement. Upwardmovement of the plunger 36 will occur until the collar 45 bottoms on thestop surface 46 to protect the diaphragm and to prevent build up ofpressure within the space 34. The amount of endwise movement which maybe undergone by the plunger element 50 before bottoming of the spring 59occurs may be tailored to approximate the range of available movement ofthe plunger 36. Any tendency for the lower plunger rod 56 to move beyondthis point is accommodated by yielding of the safety spring 60 whichpermits relative movement between the members 50, 56 as may necessary.The only exposed moveable part is the lower end of the plunger extension56 which is, moreover, largely shielded in the hollow frame member 20.This is to be contrasted with the long, exposed, and hence vulnerable,levers used in prior attempts to secure a high amplification factor.

With the construction and operational features of the above simplifiedversion of the present invention fully in mind, attention may now begiven to a more sophisticated and preferred version set forth in FIGS. 5to inclusive. In accordance with this aspect of the invention, twoseparate sensing units are provided similar in construction to the unitsset forth in FIG. 3 and coupled to separate caliper rollers arranged endto end transversely of the direction of sheet movement, each of thesensing units having a progressive series of contacts arranged atincreasing level and with logic circuitry being interposed between thecontacts and the output circuit so that when the two rollers are raisedsubstantially in step with one another, upon traversal of a stream oflapped sheets, no output signal is produced, but when one of the rollersis raised to a different degree than the other, indicating the presenceof a thickness anomaly on one side of the sheet, a signal is given toshut down the conveyor. Further in accordance with the invention, afinal or high-level contact is provided in the series which bypasses thelogic circuitry so that upon achieving a displacement beyond that whichis anticipated by either one or both of the caliper rollers, a signal isproduced to shut down the conveyor. Turning to FIGS. 5-9 inclusive,since the two adjacent installations are substantially identical to oneanother and to the embodiment previously described, correspondingreference numerals, with the addition of subscripts a or b asappropriate, have been used to indicate corresponding parts. Separatecaliper mechanisms 30a, 30b are provided under the control of rollers a,15b which are arranged end to end transversely with respect to thedirection of sheet movement. The rollers are mounted on arms 17a, ll7bpivoted on horizontal pins 18a, 1812 which are supported in brackets19a, 19b, respectively.

The sensing assembly 131a (FIG. 9) is specifically different from thatearlier disclosed, having a base 132a and a cap 133a defining a centralchamber llMa which is enclosed, at the bottom, by a diaphragm 1350supported on a plunger disc 137a forming part of plunger 136a. In thisembodiment the neck portion which communicates with the chamber 134 ismade up of four separate necks I41al44a, having individual adjustablecontacts ll45a-148a, respectively. The necks are preferably located in asymmetrical four-sided cluster as shown in FIG. 8. Upon upward movementof the diaphragm 135a, a column of conductive liquid rises in the sameway in each, since each neck is of the same diameter and equallyaccessible to the body of the liquid. Thus, as the diaphragm 135a movesupwardly, the contacts are progressively engaged. The contact 1450 may,for example, be adjusted so that contact is made when one thickness ofpaper is under the roller. Contact 146a may be adjusted for twothicknesses and 1470 adjusted for three. All of these thicknesses arewithin the normally expected range of thickness assuming overlap inaccordance with the pattern of FIG. 2. The high-level contact 148a isadjusted to produce contact when the total thickness, detected by theassociated roller, exceeds the maximum expected; for example, contact1480 may be adjusted to close the circuit when any thicknesssubstantially over that corresponding to three sheets is encountered.

ln carrying out the present invention the sensing assembly of thecaliper unit 30b'is provided with the same number of contacts similarlyarranged and similarly adjusted. As shown in the right-hand portion ofFIG. 9, the second sensing assembly is indicated at 13111, andcorresponding numerals with subscript b are used to denote correspondingparts.

Thus, contacts 145a, I45b are adjusted to similar height and correspondto one another, the same is true for contacts 146a, M611 and 147a, l47b.The body of conductive liquid in each of the devices, forming the otherside of the switch, has been identified for convenience as contacts150a, 15%.

In accordance with one aspect of the invention, logic circuitry isprovided so that simultaneous making of the paired contacts l4l5a,1145b, etc., denoting a completely symmetrical state, will be considereda perfectly safe condition and one not to produce an output signal,whereas the making of one contact of the pair, but not the other, willbe understood to denote a nonsymmetrical condition for the purpose ofproducing an output signal for sounding of an alarm for automaticshutdown of the conveyor. The logic circuitry, is in the form ofmagnetic relays connected to each of the progressive level contactsexcept the last in the series, each of the relays having a normally openand normally closed contacts and with the normally opened contact of onerelay being connected in series with the normally closed contact of therelay of the paired level contact.

Referring to FIG. 10, the circuit includes a transformer 160 connectedto the regular AC supply and having voltage lines 161i, 162 and aswitched or output line 163. The lowest level contact a, which isengaged first by the body liquid 1150a, has, connected in series, thewinding of a relay a having a normal open contact 155110 and a normallyclosed circuit contact 155ac. The corresponding lowest level contact145!) in the second sensing assembly, indicated at 1145b, is connectedto a relay I55b having a normally closed contact 155120 and a normallyopen contact I55b0. The normally open and normally closed contacts ofthe respective relays are, as shown, connected in series from thevoltage line 162 to the switched line 1163.

Similarly, relays 156a, 157a, l57b are connected to terminals atsuccessively higher level, all of the relays being provided with thenormally open and nonnally closed contacts designated by the suffix 0"and c" and connected as shown, the normally open contact being connectedin series with the normally closed contact on the relay with which it ispaired.

For producing an output signal, a time delay relay 170, having a delaytime on make on the order of 0.005 second is provided, connected fromthe switched line 163 to the voltage line 161. The time delay relay hasa normally open sealing" contact 171 connected across lines 162463 inseries with a reset pushbutton PB and a normally closed output contact172 which is connected in series with the existing trip solenoid 175. Itwill be understood that the opening of the circuit of the trip solenoid175, permitting such solenoid to drop out, is utilized, in the usualway, to disengage the conveyor and press drive, either by deenergizingthe drive motor or by deenergizing a clutch connected to the shaft ofthe drive motor. The normally closed contact is, therefore, analogous tothe emergency stop button provided in substantially all commercial pressand conveyor drives.

In operation, then, it will be apparent that when the paired levelcontacts are both engaged by columns of conductive liquid substantiallysimultaneously, within the range of expected thickness, no output signalresults. This may be made clear by assuming that the rollers 15a, 15bare both in current running engagement with two sheet thicknesses,causing simultaneous closing of the level contacts 146a, 1461). This hasthe effect of opening the normally closed contacts and closing thenormally open contacts on each of the two relays 156a, 156b, so that nocircuit is made between lines 162, I63, and the time delay relay is notenergized. Let it be assumed further that the rollers 15a, 15bsimultaneously roll up upon a triple sheet thickness. This causes themaking of contacts 147a, 1147b in the two sensing assemblies resultingenergization of the paired relays simply interchanges the condition ofthe normally open and normally closed contacts and no circuit is madeacross the lines 162, 163 so that the time delay relay remainsunenergized.

However, suppose that the rollers llSa, 15b because of a skewed sheet,are not simultaneously subjected to three sheet thicknesses. Supposeonly two thicknesses exist under the roller 15a while three thicknessescurrently exist under the roller 15b. This causes the level contact11470 to be made in advance of the making of the paired contact l47b sothat the relay 157a is turned on before the relay I57b. This causes thenormally open contact 15700 to be closed at the time that contact ll57bcon the paired relay is still closed so that a circuit is completedbetween the lines 162, 163, thus energizing the lower terminal of thetime delay relay 170. After a short time delay this relay closes itssealing contact 171 so that it seals itself in through reset pushbuttonPB. At the same time normally closed contact 172 in series with the tripsolenoid 175 opens, permitting the latter to drop out and shutting downthe conveyor and press.

In the same way any nonsimultaneous making or breaking of the pairedlevel contacts, regardless of the reason for the dissymmetry of thetotal sheet thickness, will have the effect of energizing the time delayrelay 170 to produce closing down of the conveyor drive.

It is one of the features of the present control circuit that a finalcontact is provided in the level series of each of the sensingassemblies which detects excessive thickness engaged by either or bothof the caliper rollers a, 15b. in order to bypass the logic circuit andto enable such closure, upon excess thickness, to act directly upon thetime delay relay 170, relays are omitted in these lines and the finallevel contacts 148a and l48b are both connected directly as shown, tothe lower terminal of the time delay relay. Thus, in the event a smallwad of paper becomes lodged between the overlapping sheets to provide athickness anomaly, this fact is immediately detected by displacement ofroller 15a or 15b to produce direct energization of the time delay relay170, as an incident of which such relay seals itself in and drops outits normally closed contact 171 to deenergize the trip solenoid 175. Thecircuit is restored by pushing the pushbutton PB to drop out the timedelay relay.

While the invention has been described in connection with the use ofmagnetic relays in the logic circuitry, it will be apparent that theinvention is not limited thereto and that the relay means may be in theform of corresponding solid-state logic circuitry without departing fromthe invention.

It will also be apparent to one skilled in the art that the invention isnot limited to the use of any particular conducting liquid. Mercury is,however, preferred. While mercury is a heavy liquid, the necks whichenclose the level contacts are of small diameter and the chambersindicated at 34, 1340, 13411, in the drawings may be made relativelythin in vertical dimension so that only a limited total mass of mercuryis involved, an amount which is small compared to the effectiveoperating forces.

The term roller" has been used herein to designate the elements 15, 15aand 15b. While the disclosed structure is preferred for riding upon thetop of the sheets, it will be understood that the term roller" as usedherein shall be understood to include, within its scope, any equivalentriding means such as stationary riders having a highly polished,frictionless engaging surface.

The diaphragm 35 may be of any suitable material capable of repeatedflexure without breakage or fatigue. When the diaphragm is made ofmaterial which is electrically nonconductive, for example rubberlikematerial or durable plastic, the rivet which secures the diaphragm ismade of metal to serve as a conductor to insure that the conductiveliquid is electrically grounded. While the term diaphragm" has been usedto described elements 35, 135a and 135b, and while use of diaphragm inthe form of a disc is preferred, it will be understood that the term isbroad enough to contemplate use of an analogously operating, closelyfitted piston without in any way departing from the present invention.Also while the diaphragm is stated to enclose the lower surface of thechamber, it will be understood that the term lower" is a relative oneand that the diaphragm need not be horizontal.

Moreover, while the preferred construction includes level contacts whichenter from the upper end of the neck, it will be apparent that theinvention is not limited to this particular contact arrangement and thatthe contacts may be mounted to enter the neck regions from the siderather than from the top. Indeed, while four separate neck portions areshown in FIG. 9, it would be possible, and in some instances practical,to employ but a single neck with four contacts progressively engaged bythe rising liquid level.

Also the term plunger" has been used to designate the means for couplingthe diaphragm to the associated roller. As will be clear, the plungermay be a single element, either long or short, or may be, as shown, madeup of a composite of several plunger elements that cooperate with oneanother, end to end, to displace the diaphragm.

While no mention has been made of the provision for venting the neck, ornecks, in the disclosed devices to permit rapid rise and fall ofconducting liquid, it will be understood that suitable vents may beincorporated, for example, by providing a nonsealing fit between theferrules which mount the contacts and the surrounding body or capofinsulating material.

What I claim is:

1. In a caliper mechanism for lapped sheets to fed to a printing pressor the like, the combination comprising;

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

a sensing roller at the reference position guided for up and downmovement,

a plunger coupled to the roller for movement therewith,

a sensing assembly defining a liquid chamber having an upwardlyextending neck portion,

a diaphragm covering the underside of the chamber, the

diaphragm being coupled to the plunger,

a body of conductive liquid in the chamber,

an electrical contact at the upper end of the neck portion,

the cross-sectional area of the neck portion being only a small fractionof the area of the diaphragm so that when the roller moves upwardly byan amount which exceeds the normal thickness of the sheet, a column ofthe liquid is forced upwardly in the neck portion at an amplified ratefor engaging the contact, and

means for signaling engagement of the contact.

2. The combination as claimed in claim 1 in which the plunger has stopsfor severely limiting its movement in both directions in the sensingassembly.

3. The combination as claimed in claim 1 in which the plunger has a stopfor limiting upward movement of the plunger as well as the diaphragmwhich is connected to it and in which the plunger has a bottoming-typeyieldable connection to permit accommodation to excess upward movementof the roller.

4. The combination as claimed in claim 1 in which lost motion isprovided in the plunger thereby to permit movement of the roller throughan initial displacement prior to displacement of the liquid.

5. The combination as claimed in claim 1 in which the electrical contactis axially positionable in the neck portion.

6. The combination as claimed in claim I in which a plurality ofcontacts are provided in the neck portion and in which each contact hasassociated signaling means and is at a different level.

7. In a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising;

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

a sensing roller at the reference position guided for up and downmovement,

a relatively fixed mount,

a plunger coupled to the roller for movement therewith relative to themount,

a sensing assembly defining a liquid chamber having an upwardlyextending neck portion,

a diaphragm covering the underside of the chamber and coupled to theplunger,

a body of conductive liquid in the chamber,

an electrical contact at the upper end of the neck portion,

the cross-sectional area of the neck portion being only a small fractionof the area of the diaphragm so that when the roller moves upwardly acolumn of the liquid is forced upwardly in the neck portion forengagement with the contact, and

the sensing assembly having a threaded connection with the mountcoaxially arranged with respect to the plunger thereby to predeterminethe point of making contact as a function of sheet thickness.

8. in a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising:

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

a frame,

a sensing roller at the reference position guided for up and downmovement with respect the the frame,

a mount secured to the frame,

the sensing assembly being secured to the mount,

the sensing assembly defining a liquid chamber having an upwardlyextending neck portion,

a diaphragm covering the underside of the chamber,

a body conductive liquid in the chamber,

an electrical contact at the upper end of the neck portion,

plunger means extending though the mount into engagement with thediaphragm at its upper end and connected to the roller at its lower end,

a bottoming stop for limiting the downward extension of the plungermeans,

a threaded connection between the mount and the frame for adjusting thenormal position of the roller, and

a threaded connection between the sensing assembly and the mount forpredetermining the degree of movement of the plunger means which isrequired to produce electrical contact.

9. The combination as claimed in claim 8 in which the plunger meansincludes a bottomingtype yielding connection for permitting excessroller displacement free of accompanying movement of the plunger.

10. In a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising;

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

a frame,

a sensing roller at the reference position guided for up and downmovement with respect to the frame,

a cylindrical mount,

a lower plunger centered in the mount and connected at its lower end tothe sensing roller,

a cylindrical sensing assembly defining a liquid chamber having anupwardly extending neck portion,

a diaphragm enclosing the underside of the chamber,

a body of conductive liquid in the chamber,

an electrical contact at the upper end of the neck portion,

an upper plunger axially mounted in the sensing assembly connected tothe diaphragm at its upper end and arranged for engagement with thelower plunger at its lower end, each of the plungers having means forurging them downwardly into bottomed condition,

the mount being telescopingly threaded with respect to the frame foradjustment of the normal position of the roller, and the sensingassembly being telescopingly threaded into the mount for predeterminingthe amount of roller and plunger movement required for the making ofelectrical contact, and

the cross-sectional area of the neck portion being only a small fractionof the area of the diaphragm so that when the roller moves upwardly acolumn of the liquid is forced upwardly in the neck portion at a ratewhich is a large multiple of roller movement.

11. The combination as claimed in claim 10 which stops are provided inthe sensing assembly for limiting the movement of the upper plunger ineach direction and in which stops are provided in the mount for limitingthe degree of movement of the lower plunger in each direction, each ofthe plungers having a spring for urging the same into a bottomedcondition.

12. In a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising;

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

ill

a pair of sensing rollers transversely arranged end to end at thereference position and guided for independent up and down movement inaccordance with the thickness of the sheets,

a pair of sensing assemblies each defining a liquid chamber having anupwardly extending neck portion,

each chamber having an enclosing diaphragm with the diaphragms beingcoupled to their respective rollers for movement therewith,

conductive liquid in the chambers,

electrical contacts in the respective neck portions, and

signaling means connected to the contacts and responsive to the makingof contact for indicating passage of a localized region of excess sheetthickness.

13. In a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising;

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

a pair of sensing rollers transversely arranged end to end at thereference position and guided for independent up and down movement inaccordance with the thickness of the sheets,

a pair of sensing assemblies each defining a liquid chamber having anupwardly extending neck portion,

each chamber having an enclosing diaphragm with the diaphragms beingcoupled to the respective rollers for movement therewith,

a body of conductive liquid in each of the chambers,

electrical contacts at the same relative level in the respective neckportions, and

signaling means including logic circuitry responsive to the making ofone but not both of the electrical contacts to indicate nonsymmetry inthe thickness of the portions of the sheets engaged by the respectiverollers.

14. The combination as claimed in claim 13 in which relays havingnormally open and normally closed contacts are connected to therespective electrical contact with the normally open and normally closedcontacts of the relays being connected in series with one another acrossa signaling circuit so that closure of one of the relays without closureof the other produces an output signal.

15. The combination as claimed in claim 14 in which a time delay deviceis interposed in series with the output circuit so that no output signalis produced except upon sustained closure of only one of the relays fora predetermined minimum time interval.

16. In a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising:

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

a pair of sensing rollers transversely arranged end to end at thereference position and guided for independent up and down movement inaccordance with the thickness of the engaged portions of the sheets,

a pair of sensing assemblies each defining a liquid chamber having anupwardly extending neck portion,

each chamber having an enclosing diaphragm with the diaphragms beingcoupled to the respective rollers for movement therewith,

bodies of conductive liquid in the chambers,

each of the neck portions having a series of contacts arranged atprogressive increments and positioned for simultaneous respectiveengagement in pairs when the rollers encounter sheets overlapped to thesame total thickness,

an output circuit, and

means responsive to the making of one only of a pair of correspondingcontacts thereby indicating a condition of nonsymmetry between thecondition of the two rollers for the production of an output signal.

17. The combination as claimed in claim 16 in which the series ofcontacts in each of the neck portions includes an end contact and inwhich means are provided for producing a signal in the output circuitwhen either of the end contacts is engaged.

18. In a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising:

a generally horizontal conveyor for carrying a stream of lapped sheetspast a reference position,

a pair of sensing rollers transversely arranged end to end at thereference position and guided for independent up and down movement inaccordance with the thickness of the engaged portions of the sheets,

a pair of sensing assemblies each defining a liquid chamber having anupwardly extending neck portion including a plurality of necks,

each chamber having an enclosing diaphragm with the diaphragms beingcoupled to the respective rollers for movement therewith,

a body of conducting liquid in each of the chambers,

the cross-sectional area of the necks being a small fraction of theareas of the diaphragms so that when the rollers move upwardly by anequal amount the columns of liquid in the necks are forced upwardly byan equal amount at an amplified rate,

the necks of each sensing assembly having a series of level contactsengageable by the columns of liquid at respectively correspondingelevations indicative of equal sheet thickness,

each of the level contacts being connected to a relay being havingnormally open and normally closed circuits,

an output circuit, and

the normally open circuit of one relay being connected in series withthe normally closed circuit of the corresponding relay across the outputcircuit so that the output circuit is closed only when the rollers areat a differential level indicating a thickness anomaly in the portion ofthe sheets engaged by one of the rollers.

19. The combination as claimed in claim 18 in which highlevel contactsare provided in each of the necks with each of the high-level contactsbeing connected directly to the output circuit for closing the outputcircuit when either one of the two rollers is subjected to excessivedisplacement.

20. The combination as claimed in claim 19 in which a time delay deviceis incorporated in the output circuit to provide brief time delaythereby to preclude passage of an output signal in response to transientmovements of the rollers.

3,625,509 December 7, 1971 Patent No. Dated Inv t j Carlton C. ClaybournIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 2, line 23, change "contact" to read "contacts".

Colunn 3, line 75, change "of" to read "off".

Column 4, line 28, change "bottom" to read "bottoming";

line 51, change "When" to read "Where";

line 53, change "product" to read "produce";

line 70, after "may" insert ---be--.

Column 6, line line 14, after "body" insert of---;

line 25, after "157a" insert --and l56b,---;

line 60, after "resulting" insert --in--;

line 61, after "the" (first occurrence) insert ---connected relays 157a,l57b. Again,

simultaneous energization of the---.

Column 7, line 58, change "described" to read "describe".

001mm 8, line 14, after "sheets" delete "to" (first occurrence).

RM P0405!) (1M9! uscomm-nc OOSTG-PSB ",5. GOVIIHI IINT PRINTING OFFICE:l9! 0-365-334.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 625509 Dated December 7 1971 Inventor) Carlton C. Claybourn PAGE 2 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 9, line 11, after "respect" delete "the" and insert line 17,after "body" insert ---of---;

Column 10, line 37, change "contact" to read "contacts".

Column 12, line 3, delete "being".

Signed and sealed this 13th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR.

Commissioner of Patents 2M PO-105O (10-69) USCOMM-DC 80376-P69 1r u.s,eovnmuur mun-mo ornce; nu c-su-su.

1. In a caliper mechanism for lapped sheets fed to a printing press orthe like, the combination comprising; a generally horizontal conveyorfor carrying a stream of lapped sheets past a reference position, asensing roller at the reference position guided for up and downmovement, a plunger coupled to the roller for movement therewith, asensing assembly defining a liquid chamber having an upwardly extendingneck portion, a diaphragm covering the underside of the chamber, thediaphragm being coupled to the plunger, a body of conductive liquid inthe chamber, an electrical contact at the upper end of the neck portion,the cross-sectional area of the neck portion being only a small fractionof the area of the diaphragm so that when the roller moves upwardly byan amount which exceeds the normal thickness of the sheet, a column ofthe liquid is forced upwardly in the neck portion at an amplified ratefor engaging the contact, and means for signaling engagement of thecontact.
 2. The combination as claimed in claim 1 in which the plungerhas stops for severely limiting its movement in both directions in thesensing assembly.
 3. The combination as claimed in claim 1 in which theplunger has a stop for limiting upward movement of the plunger as wellas the diaphragm which is connected to it and in which the plunger has abottoming-type yieldable connection to permit accommodation to excessupward movement of the roller.
 4. The combination as claimed in claim 1in which lost motion is provided in the plunger thereby to permitmovement of the roller through an initial displacement prior todisplacement of the liquid.
 5. The combination as claimed in claim 1 inwhich the electrical contact is axially positionable in the neckportion.
 6. The combination as claimed in claim 1 in which a pluralityof contacts are provided in the neck portion and in which each contacthas associated signaling means and is at a different level.
 7. In acaliper mechanism for lapped sheets fed to a printing press or the like,the combination comprising; a generally horizontal conveyor for carryinga stream of lapped sheets past a reference position, a sensing roller atthe reference position guided for up and down movement, a relativelyfixed mount, a plunger coupled to the roller for movement therewithrelative to the mount, a sensing assembly defining a liquid chamberhaving an upwardly extending neck portion, a diaphragm covering theunderside of the chamber and coupled to the plunger, a body ofconductive liquid in the chamber, an electrical contact at the upper endof the neck portion, The cross-sectional area of the neck portion beingonly a small fraction of the area of the diaphragm so that when theroller moves upwardly a column of the liquid is forced upwardly in theneck portion for engagement with the contact, and the sensing assemblyhaving a threaded connection with the mount coaxially arranged withrespect to the plunger thereby to predetermine the point of makingcontact as a function of sheet thickness.
 8. In a caliper mechanism forlapped sheets fed to a printing press or the like, the combinationcomprising: a generally horizontal conveyor for carrying a stream oflapped sheets past a reference position, a frame, a sensing roller atthe reference position guided for up and down movement with respect tothe frame, a mount secured to the frame, the sensing assembly beingsecured to the mount, the sensing assembly defining a liquid chamberhaving an upwardly extending neck portion, a diaphragm covering theunderside of the chamber, a body of conductive liquid in the chamber, anelectrical contact at the upper end of the neck portion, plunger meansextending though the mount into engagement with the diaphragm at itsupper end and connected to the roller at its lower end, a bottoming stopfor limiting the downward extension of the plunger means, a threadedconnection between the mount and the frame for adjusting the normalposition of the roller, and a threaded connection between the sensingassembly and the mount for predetermining the degree of movement of theplunger means which is required to produce electrical contact.
 9. Thecombination as claimed in claim 8 in which the plunger means includes abottoming-type yielding connection for permitting excess rollerdisplacement free of accompanying movement of the plunger.
 10. In acaliper mechanism for lapped sheets fed to a printing press or the like,the combination comprising; a generally horizontal conveyor for carryinga stream of lapped sheets past a reference position, a frame, a sensingroller at the reference position guided for up and down movement withrespect to the frame, a cylindrical mount, a lower plunger centered inthe mount and connected at its lower end to the sensing roller, acylindrical sensing assembly defining a liquid chamber having anupwardly extending neck portion, a diaphragm enclosing the underside ofthe chamber, a body of conductive liquid in the chamber, an electricalcontact at the upper end of the neck portion, an upper plunger axiallymounted in the sensing assembly connected to the diaphragm at its upperend and arranged for engagement with the lower plunger at its lower end,each of the plungers having means for urging them downwardly intobottomed condition, the mount being telescopingly threaded with respectto the frame for adjustment of the normal position of the roller, andthe sensing assembly being telescopingly threaded into the mount forpredetermining the amount of roller and plunger movement required forthe making of electrical contact, and the cross-sectional area of theneck portion being only a small fraction of the area of the diaphragm sothat when the roller moves upwardly a column of the liquid is forcedupwardly in the neck portion at a rate which is a large multiple ofroller movement.
 11. The combination as claimed in claim 10 which stopsare provided in the sensing assembly for limiting the movement of theupper plunger in each direction and in which stops are provided in themount for limiting the degree of movement of the lower plunger in eachdirection, each of the plungers having a spring for urging the same intoa bottomed condition.
 12. In a caliper mechanism for lapped sheets fedto a printing press or the like, the combination comprising; a generallyhorizontal conveyor for carrying a stream of lapped sheets past areference position, a pair of sensing rollers transversely arrAnged endto end at the reference position and guided for independent up and downmovement in accordance with the thickness of the sheets, a pair ofsensing assemblies each defining a liquid chamber having an upwardlyextending neck portion, each chamber having an enclosing diaphragm withthe diaphragms being coupled to their respective rollers for movementtherewith, conductive liquid in the chambers, electrical contacts in therespective neck portions, and signaling means connected to the contactsand responsive to the making of contact for indicating passage of alocalized region of excess sheet thickness.
 13. In a caliper mechanismfor lapped sheets fed to a printing press or the like, the combinationcomprising; a generally horizontal conveyor for carrying a stream oflapped sheets past a reference position, a pair of sensing rollerstransversely arranged end to end at the reference position and guidedfor independent up and down movement in accordance with the thickness ofthe sheets, a pair of sensing assemblies each defining a liquid chamberhaving an upwardly extending neck portion, each chamber having anenclosing diaphragm with the diaphragms being coupled to the respectiverollers for movement therewith, a body of conductive liquid in each ofthe chambers, electrical contacts at the same relative level in therespective neck portions, and signaling means including logic circuitryresponsive to the making of one but not both of the electrical contactsto indicate nonsymmetry in the thickness of the portions of the sheetsengaged by the respective rollers.
 14. The combination as claimed inclaim 13 in which relays having normally open and normally closedcontacts are connected to the respective electrical contacts with thenormally open and normally closed contacts of the relays being connectedin series with one another across a signaling circuit so that closure ofone of the relays without closure of the other produces an outputsignal.
 15. The combination as claimed in claim 14 in which a time delaydevice is interposed in series with the output circuit so that no outputsignal is produced except upon sustained closure of only one of therelays for a predetermined minimum time interval.
 16. In a calipermechanism for lapped sheets fed to a printing press or the like, thecombination comprising: a generally horizontal conveyor for carrying astream of lapped sheets past a reference position, a pair of sensingrollers transversely arranged end to end at the reference position andguided for independent up and down movement in accordance with thethickness of the engaged portions of the sheets, a pair of sensingassemblies each defining a liquid chamber having an upwardly extendingneck portion, each chamber having an enclosing diaphragm with thediaphragms being coupled to the respective rollers for movementtherewith, bodies of conductive liquid in the chambers, each of the neckportions having a series of contacts arranged at progressive incrementsand positioned for simultaneous respective engagement in pairs when therollers encounter sheets overlapped to the same total thickness, anoutput circuit, and means responsive to the making of one only of a pairof corresponding contacts thereby indicating a condition of nonsymmetrybetween the condition of the two rollers for the production of an outputsignal.
 17. The combination as claimed in claim 16 in which the seriesof contacts in each of the neck portions includes an end contact and inwhich means are provided for producing a signal in the output circuitwhen either of the end contacts is engaged.
 18. In a caliper mechanismfor lapped sheets fed to a printing press or the like, the combinationcomprising: a generally horizontal conveyor for carrying a stream oflapped sheets past a reference position, a pair of sensing rollerstransversely arranged end to end at the reference position and guidedfor independent up and down movement in accordance with the thickness ofthe engaged portions of the sheets, a pair of sensing assemblies eachdefining a liquid chamber having an upwardly extending neck portionincluding a plurality of necks, each chamber having an enclosingdiaphragm with the diaphragms being coupled to the respective rollersfor movement therewith, a body of conducting liquid in each of thechambers, the cross-sectional area of the necks being a small fractionof the areas of the diaphragms so that when the rollers move upwardly byan equal amount the columns of liquid in the necks are forced upwardlyby an equal amount at an amplified rate, the necks of each sensingassembly having a series of level contacts engageable by the columns ofliquid at respectively corresponding elevations indicative of equalsheet thickness, each of the level contacts being connected to a relayhaving normally open and normally closed circuits, an output circuit,and the normally open circuit of one relay being connected in serieswith the normally closed circuit of the corresponding relay across theoutput circuit so that the output circuit is closed only when therollers are at a differential level indicating a thickness anomaly inthe portion of the sheets engaged by one of the rollers.
 19. Thecombination as claimed in claim 18 in which high-level contacts areprovided in each of the necks with each of the high-level contacts beingconnected directly to the output circuit for closing the output circuitwhen either one of the two rollers is subjected to excessivedisplacement.
 20. The combination as claimed in claim 19 in which a timedelay device is incorporated in the output circuit to provide brief timedelay thereby to preclude passage of an output signal in response totransient movements of the rollers.